1. Technical Field
The present invention relates in general to sharing resources in data processing systems and in particular to reallocating resources between logical partitions of a data processing system. Still more particularly, the present invention relates to a system, method and computer program product for optimizing allocation of resources to partitions of a data processing system.
2. Description of the Related Art
Logical partitioning (LPAR) of a data processing system permits several concurrent instances of one or more operating systems on a single processor, thereby providing users with the ability to split a single physical data processing system into several independent logical data processing systems capable of running applications in multiple, independent environments simultaneously. For example, logical partitioning makes it possible for a user to run a single application using different sets of data on separate partitions, as if the application was running independently on separate physical systems.
Partitioning has evolved from a predominantly physical scheme, based on hardware boundaries, to one that allows for virtual and shared resources, with load balancing. The factors that have driven partitioning have persisted from the first partitioned mainframes to the modern server of today. Logical partitioning is achieved by distributing the resources of a single system to create multiple, independent logical systems within the same physical system. The resulting logical structure consists of a primary partition and one or more secondary partitions.
The ability of a partitioned data processing system both to create and to close or dissolve concurrent instances of one or more operating systems on a single processor creates numerous technological challenges with regard to the migration of resources and processes from one partition to another. Uncapped sub-processor partitions (i.e., partitions for which resource limitations are not enforced) allow for the exploitation of idle time on a system by ‘expanding’ the partition to use more processing cycles when available. Existing embodiments of uncapped partitions, however, limit the amount of expansion of the partition to the total number of virtual CPUs allotted to that partition. This limiting action is a burdensome limit imposed on the parallelization of jobs in the partition.
What is needed is a system, method and computer program product for optimizing allocation of resources to partitions of a data processing system.